Afternotes:I have not applied Eliovp's Nano mod yet but I have a 5 x Sapphire R9-Nano rig in production with settings:-100mV, 1125, 300 delivering total 133.6MHs (ETH), 2004MHs (DCR) at only 1005watts.With his mod, 6 x GPUs yields 185MHs using just over 1000 watts!

It will consume a lot of power. With the 1120 Core frequency, some cards will work with -100 mV. That will save you 20% energy.

Thank you for suggestion

I actually put all values to default - but mining speed remains on the level of 32MHs

So will leave like that for couple of hours

The 390 is power hogger, I once metered it at 270w per GPU full speed (31-32MHs) and at 6 cards, almost 2000w (when dual mining), when I had to do a 2 x PSU setup (1300w x 2).

Although it was nice to get a monster rig at 185-190MHs but you sacrifice a PSU (which you could have used for 2nd rig) and drawing too much power from a 20A power point (dangerous). Keeping this setting this way will be too dangerous and will surely kill your PSU sooner or later.

With several good tips from Philip and other senior members, I settled for 5 x PSU design, with max underclocking and slight overclocking using Afterburner. I may sacrifice some MHs, but it keeps the rig investment safe and also prolong life of PSU and avoid shorting your whole house! Also, you can certainly get more MHs from 2 rigs with 1 PSU each (ie. 5 x 390 = 151MHs with 1600w PSU, times 2 = 302 MHs total for 2 identical rigs).

It will consume a lot of power. With the 1120 Core frequency, some cards will work with -100 mV. That will save you 20% energy.

Thank you for suggestion

I actually put all values to default - but mining speed remains on the level of 32MHs

So will leave like that for couple of hours

The 390 is power hogger, I once metered it at 270w per GPU full speed (31-32MHs) and at 6 cards, almost 2000w (when dual mining), when I had to do a 2 x PSU setup (1300w x 2).

Although it was nice to get a monster rig at 185-190MHs but you sacrifice a PSU (which you could have used for 2nd rig) and drawing too much power from a 20A power point (dangerous). Keeping this setting this way will be too dangerous and will surely kill your PSU sooner or later.

With several good tips from Philip and other senior members, I settled for 5 x PSU design, with max underclocking and slight overclocking using Afterburner. I may sacrifice some MHs, but it keeps the rig investment safe and also prolong life of PSU and avoid shorting your whole house! Also, you can certainly get more MHs from 2 rigs with 1 PSU each (ie. 5 x 390 = 151MHs with 1600w PSU, times 2 = 302 MHs total for 2 identical rigs).

Also, you can certainly get more MHs from 2 rigs with 1 PSU each (ie. 5 x 390 = 151MHs with 1600w PSU, times 2 = 302 MHs total for 2 identical rigs).

All make sense!

Question - I have 2x R9 390 on one 850W PSU

Is it safe to use it 24x7 with default GPU settings?

A good PSU (ie. EVGA-Gold, Platinum) will let you exceed the limit for spikes etc. but I don't think design of PSU is for you to constantly over the limit. Infact, a good practise is to consume 80% of the PSU so that there is safe buffer. This will surely keep the PSU running safe and within limits. This would also mean that your other components like mobo, GPUs, CPU etc are kept optimally powered... so your overall investment is protected and perhaps your chances of recycling or selling them off in the future is very good.

Mining is 24x7 affair (unless your need to cut back during summer etc), 850w PSU is good enough for 2 x GPU rig, running 24x7, as long as you have proper cooling like fans etc. The 390s runs very hot.

2) extension outlet (live and neutral wires are separated) >>>> you have two hot wires and a ground you may or may not have a neutral in a 240 volt circuit.

i already have a clamp meter with a volt meter that looks like this.

ill measure amps and volts

ohms law say amps x volts = watts

Please support sidehack with his new miner project Send to : 1BURGERAXHH6Yi6LRybRJK7ybEm5m5HwTrI mine alt coins with https://simplemining.net I see BTC as the super highway and alt coins as taxis and trucks needed to move transactions.

It will consume a lot of power. With the 1120 Core frequency, some cards will work with -100 mV. That will save you 20% energy.

Thank you for suggestion

I actually put all values to default - but mining speed remains on the level of 32MHs

So will leave like that for couple of hours

The 390 is power hogger, I once metered it at 270w per GPU full speed (31-32MHs) and at 6 cards, almost 2000w (when dual mining), when I had to do a 2 x PSU setup (1300w x 2).

Although it was nice to get a monster rig at 185-190MHs but you sacrifice a PSU (which you could have used for 2nd rig) and drawing too much power from a 20A power point (dangerous). Keeping this setting this way will be too dangerous and will surely kill your PSU sooner or later.

With several good tips from Philip and other senior members, I settled for 5 x PSU design, with max underclocking and slight overclocking using Afterburner. I may sacrifice some MHs, but it keeps the rig investment safe and also prolong life of PSU and avoid shorting your whole house! Also, you can certainly get more MHs from 2 rigs with 1 PSU each (ie. 5 x 390 = 151MHs with 1600w PSU, times 2 = 302 MHs total for 2 identical rigs).

I am mining with qtminer just eth coin I spend 2500 watts for about 310mh you are spending more watts about 2800 for dual mining. I am maxed for heat it was 92f today and I can't run more power then the 2400-2500 watts. So we are near the same hash what do you eran with the second coin?i figure it cost you 400 - 600 more watts which is 12 kwatts a day and maybe 360 -375 kwatts a month.at my insane summer prices of 18 cents I need 67.50 $ in extra power about 2.25$ a day does the second coin earn $5 a day?

Please support sidehack with his new miner project Send to : 1BURGERAXHH6Yi6LRybRJK7ybEm5m5HwTrI mine alt coins with https://simplemining.net I see BTC as the super highway and alt coins as taxis and trucks needed to move transactions.

My most recent "monster" came in this case - Newegg "Avatar Scryptminer" unit that I seem to have gotten the last one of (they have a different version with a higher-end CPU but only 2 GPUs still available, same price IIRC).I did swap one of my R9 290s into it in place of one of the R9 280x it came with, and might swap one of the other 280x for a 290 out of one of my other systems for better cooling.For scale - it's 25-26 inches long AND high - biggest case I've ever worked with.

I figure it will, LONG term, become a serious file server, and short-to-medium term my "system to clone" machine. I don't think I've ever seen a non-propriatary motherboard (including ALL of the EATX multi-CPU boards I've worked with) it won't fit EASILY. The one down side it the bloody massive SIDE air intake - front intake is fair but won't fit 38mm fans as far as I can tell and the drive cage blocks a lot of the airflow from the front. Lots of top and bottom intake area though, even if I used dual PS (it's specifically designed to fit 2 standard ATX power supplies) - and with riser(2), it will fit *5* dual-slot cards IN THE CASE by design (or if you could find the RIGHT motherboard possibly without the risers). The Biostar below + 1x 1-16 riser would work for 5 cards that way - no cutting needed.

Down side - top-mounted "front panal" but this thing is soo big it almost HAS to be floor-mount, which mitigates that issue somewhat, and I DO like the "drive dock on top".

The case you listed only has 7 expansion slots - you CAN'T build a 4-card rig in it as the dual-width cards won't FIT.

I used this on a previous build - it works but I'm not real happy with it overall.

Can't mount 38mm fans in the front without cutting some of the plastic off on the inside of the front panal, and I'm finding the top-mounted "front panal" stuff to be a pain to work with. Your milage might vary.

Was thinking about that one for a 4-blower-type-GPU build at one point. Biostar don't have a HUGE great rep but I've had good luck on longevity out of their motherboards, just not the highest feature or performance.

4 fairly comfortably, 3 with TONS of headroom. That's similar power consumption to my R9 290s, and I'm running 2 rigs with 2 of them and an A10-7860K VERY comfortably on the X-850 - 660 watts at the wall or some such so only pushing about 600 watts actual consumption.

Rest of the system is eating close to 100 watts - if you build a 4-way system for efficiency should work out to more like 1050ish of the 1250 rating.

4 fairly comfortably, 3 with TONS of headroom. That's similar power consumption to my R9 290s, and I'm running 2 rigs with 2 of them and an A10-7860K VERY comfortably on the X-850 - 660 watts at the wall or some such so only pushing about 600 watts actual consumption.

Rest of the system is eating close to 100 watts - if you build a 4-way system for efficiency should work out to more like 1050ish of the 1250 rating.

4x 390s even if i overclocked them all?

currently my seasonic x-1250 is powering only 3x 280x overclocked, i run 4pcs 280x last month though.. just playing it safe i revert it back to 3x 280x.. the opposite side (from the fan) of that PSU is really hot.